The present invention relates to a three-dimensional ultrasonic diagnosis apparatus for providing effective information for clinical diagnosis of myocardial ischemia. In particular, the present invention relates to an image processing technique for detecting and displaying a intra-myocardial blood flow from a three-dimensional image.
In clinical diagnosis of the heart, improvement in evaluation techniques of myocardial ischemia is one of the important issues. As an evaluation technology of such myocardial ischemia, conventionally there is known a technique for diagnosing an ischemia site of the heart that is a three-dimensional structure by visualizing coronary arteries of the heart (coronary blood flow) or myocardial perfusion as a two-dimensional ultrasonic image such as a color Doppler image, a power Doppler image, or a contrast image by a Color Doppler method using a ultrasonic diagnosis apparatus or contrast imaging method using a contrast agent.
In the meantime, in recent years, attention is focused on a three-dimensional ultrasonic diagnosis apparatus for scanning ultrasonic beams in a three-dimensional region to construct a three-dimensional image. It is expected to ensure application to clinical diagnosis using a three-dimensional ultrasonic image such as a CFM (Color Flow Mapping) image, a power Doppler image, or a 3D (three-dimensional) contrast image produced by this apparatus.
In view of applying the above mentioned three-dimensional ultrasonic diagnosis apparatus to a clinical diagnosis of the heart, however, in a three-dimensional image when the heart targeted for diagnosis is scanned three-dimensionally, blood flow in the cardiac cavity, coronary blood flow, and myocardial perfusion are displayed in a superimposed manner each other. Thus, there is a problem that these blood flow and perfusion are hardly discriminated, thus making it difficult to diagnose myocardial ischemia three-dimensionally. This problem cannot be found in the case of a conventional ultrasonic diagnosis apparatus for displaying a two-dimensional image.
The present invention has been achieved in view of such a conventional problem. It is an object of the present invention to provide information on a three-dimensional myocardial blood flow useful for clinical diagnosis by clearly displaying information on coronary blood flow of the heart or perfusion discriminated from the blood flow in the cardiac cavity even if a three-dimensional ultrasonic image is utilized.
In order to achieve the foregoing object, the inventor focused attention to adopt means for masking a blood flow image in the cardiac cavity, for example, 1) means for automatically extracting a cardiac endocardium from a ultrasonic monochrome image, thereby to mask an inside thereof; 2) means for automatically extracting the blood flow in the cardiac cavity from a Color Doppler or Power Doppler image to mask it; 3) means for automatically extracting the blood flow in the cardiac cavity from a contrast image based on a contrast imaging method using a contrast agent, thereby to mast it; and means for displaying a coronary blood flow or perfusion in the myocardium by means of MIP (Maximum or Minimum Intensity Projections), Integral Value Projection, volume rendering or the like after it has been masked by these masking means.
A three-dimensional ultrasonic diagnosis apparatus according to the present invention has been completed based on such attention.
That is, according to a first aspect of the invention, there is provided a three-dimensional ultrasonic diagnosis apparatus comprising: means for transmitting ultrasonic beams three-dimensionally to a diagnostic site including a left ventricle of the heart in a subject being examined and for receiving means for receiving ultrasonic echo signals thereof; three-dimensional data generating means for generating three-dimensional data of the diagnostic site based on the ultrasonic echo signals received by the receiving means; cardiac cavity region determining means for determining a cardiac cavity region in three-dimensional data generated by the three-dimensional data generating means; and display image generating means for generating a display image such that information at a myocardial site of the heart is identified by converting a value of the cardiac cavity region in the three-dimensional data determined by the determining means to a different value.
According to a second aspect of the invention, there is provided the apparatus according to the first, wherein the three-dimensional data generating means generates at least one of morphological information and blood flow information of the diagnostic site.
According to a third aspect of the invention, there is provided the apparatus according to the second aspect, wherein the cardiac cavity region determining means is adopted to extract a cardiac endocardium from morphological information of the diagnostic site generated by the three-dimensional data generating means, and obtain a cardiac cavity region based thereon.
According to a fourth aspect of the invention, there is provided the apparatus according to the second aspect, wherein the cardiac cavity region determining means is adopted to obtain a cardiac cavity region based on blood flow information on the diagnostic site generated by the three-dimensional data generating means.
According to a fifth aspect of the invention, there is provided the apparatus according to the third or the fourth aspect, wherein the cardiac cavity region determining means is adopted to obtain a cardiac cavity region based on three-dimensional data obtained based on ultrasonic echoes obtained in a state in which a contrast agent is injected into the subject.
According to a sixth aspect of the invention, there is provided the apparatus according to the first and fifth aspects, wherein the display image generating means is adopted to generate a display image based on data excluding the data in the cardiac cavity region in the three-dimensional data.
According to a seventh aspect of the invention, there is provided the apparatus according to the sixth aspect, wherein the display image is a two-dimensional image obtained by projection of the three-dimensional data.
According to a eighth aspect of the invention as claimed in claim 8, there is provided the apparatus according to seventh aspect, wherein the two-dimensional image is obtained by using a predetermined projection method to project brightness information on data included in a region between a boundary face of the cardiac cavity in the three-dimensional data and a reference curved surface set from the boundary face with an arbitrary distance from the reference curved surface side.
According to a ninth aspect of the invention, there is provided the apparatus according to eighth aspect, wherein the projection method has an MIP (Maximum or Minimum Intensity Projection) method.
According to a tenth aspect of the invention, there is provided the apparatus according to the eighth aspect, wherein the projection method has an integral value projection method.
According to an eleventh aspect of the invention, there is provided the apparatus according to the seventh aspect, wherein the two-dimensional image is a partial image of the three-dimensional data.
According to a twelfth aspect of the invention, there is provided the apparatus according to the eleventh aspect, wherein the partial image is included in a partial region in which the left ventricle of the heart is divided by a plane including a longer axis thereof.
According to a thirteenth aspect of the invention, there is provided the apparatus according to the twelfth aspect, wherein the apparatus further comprising means for detecting a long axis of the left ventricle of the heart based on a cardiac cavity determined by the cardiac cavity region determining means.
According to a fourteenth aspect of the invention, there is provided the apparatus according to a thirteenth aspect, wherein the means for determining the long axis of the left ventricle of the heart is means for detecting one of a plurality of inertial main axes defined by morphology of the cardiac cavity as a long axis of the left ventricle of the heart.
According to a fifteenth aspect of the invention, there is provided a three-dimensional ultrasonic diagnosis apparatus comprising: means for transmitting ultrasonic beams three-dimensionally to a diagnostic site including a left ventricle of the heart in a subject being examined and for receiving ultrasonic echo signals thereof; means for generating three-dimensional blood flow information data of the diagnostic site based on the ultrasonic echo signals received by the transmitting and receiving means; means for determining a cardiac cavity region in the blood flow information data generated by the generating means; and means for generating a display image in which blood flow information on the cardiac cavity region determined by the determining means is eliminated.
According to a sixteenth aspect of the invention, there is provided a three-dimensional ultrasonic diagnosis apparatus comprising: means for transmitting ultrasonic beams three-dimensionally to a diagnostic site including a left ventricle of the heart in a subject being examined and for receiving ultrasonic echo signals thereof; three-dimensional data generating means for generating three-dimensional blood flow information based on the ultrasonic echo signals received by the receiving means; display image generating means for generating a display image so that a region with less blood flow in a myocardial muscle of the heart is identified by differentiating an image processing method depending on a myocardial region and a cardiac cavity region of the heart based on the three-dimensional blood flow information generated by the three-dimensional data generating means; and means for displaying the display image generated by the display image generating means.
As has been described above, in a three-dimensional ultrasonic diagnosis apparatus according to the present invention, a local myocardial muscle blood flow of the entire left ventricles of the heart can be simply evaluated objectively and quantitatively, and information useful for clinical diagnosis can be provided.